Condensed Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 29, 2015	Mar. 30, 2014
Income Statement [Abstract]
Net revenue	$ 58,254us-gaap_SalesRevenueNet	$ 43,198us-gaap_SalesRevenueNet
Cost of goods sold	36,860us-gaap_CostOfGoodsAndServicesSold	28,552us-gaap_CostOfGoodsAndServicesSold
Gross margin	21,394us-gaap_GrossProfit	14,646us-gaap_GrossProfit
Operating expenses:
Research, development and engineering	5,250us-gaap_ResearchAndDevelopmentExpense	4,524us-gaap_ResearchAndDevelopmentExpense
Selling, general and administrative	8,841	7,421
Total operating expenses	14,091us-gaap_OperatingExpenses	11,945us-gaap_OperatingExpenses
Income from operations	7,303us-gaap_OperatingIncomeLoss	2,701us-gaap_OperatingIncomeLoss
Interest income (expense), net	(34)us-gaap_InterestIncomeExpenseNet	(126)us-gaap_InterestIncomeExpenseNet
Other income (expense), net	(443)us-gaap_OtherNonoperatingIncomeExpense	79us-gaap_OtherNonoperatingIncomeExpense
Income before income taxes	6,826	2,654
Provision for income taxes	521us-gaap_IncomeTaxExpenseBenefit	189us-gaap_IncomeTaxExpenseBenefit
Net income	$ 6,305us-gaap_NetIncomeLoss	$ 2,465us-gaap_NetIncomeLoss
Net income per share:
Basic (in usd per share)	$ 0.08us-gaap_EarningsPerShareBasic	$ 0.04us-gaap_EarningsPerShareBasic
Diluted (in usd per share)	$ 0.08us-gaap_EarningsPerShareDiluted	$ 0.04us-gaap_EarningsPerShareDiluted
Shares used in computing net income per share:
Basic (in shares)	74,700	66,275
Diluted (in shares)	77,265	67,971

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